<?php
/**
 * Smarty plugin
 *
 * @package Smarty
 * @subpackage PluginsShared
 */

/**
 * evaluate compiler parameter
 *
 * @param $params array
 *       	 parameter array as given to the compiler function
 * @param $index integer
 *       	 array index of the parameter to convert
 * @param $default mixed
 *       	 value to be returned if the parameter is not present
 * @return mixed evaluated value of parameter or $default
 * @throws SmartyException if parameter is not a literal (but an expression,
 *         variable, …)
 * @author Rodney Rehm
 */
function smarty_literal_compiler_param($params, $index, $default = null) {
	// not set, go default
	if (! isset ( $params [$index] )) {
		return $default;
	}
	// test if param is a literal
	if (! preg_match ( '/^([\'"]?)[a-zA-Z0-9]+(\\1)$/', $params [$index] )) {
		throw new SmartyException ( '$param[' . $index . '] is not a literal and is thus not evaluatable at compile time' );
	}
	
	$t = null;
	eval ( "\$t = " . $params [$index] . ";" );
	return $t;
}
